The present invention relates to an electronic gas-lighting device which is cheap and easy to assemble and is fittable to a metal conducting body element of an electric household appliance, in particular a cooking range of a gas cooker, to light the burners.
Cooking ranges are known featuring integrated electric/electronic gas-lighters which are operated manually by means of pushbuttons to generate a spark by which to light one of the gas burners on the range. Known gas-lighters comprise a current-discharge generating circuit connected to one or more output terminals, each of which is connected by a conducting wire to an electrode located close to a burner to be lit: the electrodes are grounded by the range to which they are fitted. A spark is therefore generated between each electrode and each burner whenever a high-voltage current discharge is generated in the circuit.
In a first known type of gas-lighter, the various electric and electronic components of the circuit are housed in a cup-shaped body defining a casing made of nonconducting (typically polymer) material and divided by an inner wall into a first and second compartment from which the supply terminals and output terminals extend respectively; the output terminals are connected to respective secondary windings of a transformer in turn connected to a voltage discharger; the windings are housed in the first compartment of the casing and are embedded in an electrically insulting polymer resin from which the supply wires of the primary winding/s emerge; the wires are connected by means of connectors or soldered to the other circuit components which are normally carried on a printed circuit together with the components of an electronic filter, if provided, for filtering any electromagnetic noise produced when generating high-voltage pulses; and the printed circuit, together with the electronic components, is housed in the second compartment which is closed by a removable cover.
Devices of the first type therefore take a long time and are expensive to assemble, on account of the electric connections between the components in the two compartments and the cost of assembling the cover on the second compartment. What is more, in such devices, all the components of the pulse generating circuit (with the exception of the transformer) are located fairly close to one another and to the supply terminals.
In a second known type of gas-lighter, the generating circuit is embedded entirely inside a block of polymer resin which therefore substitutes for the casing. Nevertheless, this type of device is also expensive to assemble, on account of all the components and respective connecting wires having to be assembled with no support available and directly inside the molds into which the resin is poured. As such, devices of this sort are only feasible if cheap labour is available.
It is an object of the present invention to provide an electronic gas-lighting device of the type described, but designed to eliminate the aforementioned drawbacks, and which, in particular, is easy, fast and cheap to assemble, may even be assembled automatically, and enables the electronic components to be located a considerable distance from the supply terminals.
According to the present invention, there is provided an electronic gas-lighting device for spark-lighting at least one respective burner on a cooking range, the device comprising a casing defined by a cup-shaped body and made of electrically insulating material; electronic high-voltage-pulse generating means housed in an inner cavity of the casing, which cavity is accessible through a mouth of the cup-shaped body opposite and facing a bottom wall of the cup-shaped body; and, for each said burner catered to, at least one output terminal connected to said electronic high-voltage-pulse generating means and housed through a respective seating duct on the casing; characterized by also comprising a connecting board carrying an electric circuit and extending the full length of the cup-shaped body; said connecting board being positioned substantially closing said mouth but still inside said cavity, and carrying, on a first face facing said cavity, all said electronic high-voltage-pulse generating means connected mechanically and electrically to one another and to the connecting board by the connecting board itself and said circuit carried by the connecting board, so that said electronic high-voltage-pulse generating means are housed in one continuous compartment defined by said cavity of the casing and by the connecting board; said electronic high-voltage-pulse generating means being embedded, together with the connecting board, in a matrix of insulating polymer resin which fills the whole of said cavity up to a point substantially flush with said mouth; said connecting board having at least one through opening enabling said polymer resin to be poured into the casing with the connecting board already positioned closing the mouth.
More specifically, the seating duct on the casing projects outwards from said bottom wall of the cup-shaped body, is integral with the cup-shaped body, and is located on the opposite side to said mouth; and said electronic high-voltage-pulse generating means comprise at least one transformer, in turn comprising a secondary winding on an insulating tubular support, and a primary winding housed inside the insulating tubular support and coaxial with the secondary winding; each end of said secondary winding being connected to a respective said output terminal, which is defined by a flat blade connector defined by two opposite faces and carried mechanically by said insulating tubular support so that said faces are parallel to the axis of said windings.
The connecting board also preferably comprises at least one supply terminal at a first longitudinal end of the connecting board, located at a first end of said casing; and at least one ground contact at a second longitudinal end of the connecting board, opposite the first and located at a second end of said casing.
The gas-lighting device according to the invention is thus extremely compact as compared with similar known devices, while at the same time being cheap and easy to produce, easy to assemble, and easy to fit onto the cooking range, and provides for easily locating a grounded electric or electronic component as far away as possible from the end with the supply terminals. This is particularly useful, for example, in the event the device comprises an electronic noise filter, grounding of which is extremely cheap and easy and involves no complex assembly operations.